草地贪夜蛾有转移危害茶树的可能

The Fall Armyworm Spodoptera frugiperda may Transfer to Damage Tea Plant (Camellia sinesis)

草地贪夜蛾(Spodoptera frugiperda)是世界性的重大迁飞性害虫,寄主范围极广。本文比较研究了草地贪夜蛾幼虫取食茶树和玉米叶片的生长适合度。试验结果表明,饲喂茶树叶片的初孵草地贪夜蛾幼虫 8 d 死亡率高达 100%。3 龄(9 日龄)草地贪夜蛾幼虫取食茶树叶片的幼虫体重增长量显著低于以玉米叶为食的幼虫;取食 3 d 和 6 d 后,以茶树叶片为食的草地贪夜蛾幼虫的体重分别是以玉米叶为食的幼虫体重的 35.58%和36.67%。取食茶树叶片的草地贪夜蛾幼虫的生长适合度明显低于取食玉米叶的幼虫。主要表现为:(1)8 d后,取食玉米叶的草地贪夜蛾 3 龄幼虫存活率比取食茶树叶片的幼虫高出 20%;(2)取食茶树叶片的草地贪夜蛾幼虫的成功化蛹率为 54.17%;(3)取食茶树叶片的草地贪夜蛾幼虫的发育历期极显著长于取食玉米叶的幼虫,且蛹重、蛹长和蛹宽极显著低于取食玉米叶的幼虫的蛹。尽管取食茶树叶片的草地贪夜蛾幼虫的生长适合度较低,但是由于茶园中存在草地贪夜蛾嗜食的杂草,初孵幼虫可以杂草为食,3 龄以上幼虫可取食茶树叶片并成功化蛹。因此,推测一旦草地贪夜蛾误迁入茶园,在茶园中的嗜食杂草被其食光后,其幼虫很有可能进一步危害茶树。

Spodoptera frugiperda is a world-class major migratory pest with a wide range of hosts.The growth fitness of S.frugiperda larvae feeding on maize and tea leaves was studied.The result shows that the mortality rate of the newly emerged larvae feeding on tea leaves was as high as 100%for 8 d.Weight gain of 3^rd instar larvae feeding on maize leaves was significantly higher than that of larvae feeding on tea leaves.After feeding for 3 d and 6 d,the weight gains of larvae feeding on tea leaves were 35.58%and 36.67%of those feeding on maize leaves respectively.Growth fitness of larvae feeding on maize leaves was significantly better than larvae feeding on tea leaves.The main manifestations are as follows:(1)the survival rate of the old larvae feeding on the maize leaves for 8 d was 20%higher than that feeding on tea leaves.(2)the pupation rate of 9-daysinstar larvae feeding on tea leaves was 54.17%.(3)the developmental period of the larvae feeding on tea leaves was significantly longer than that of the larvae feeding on the maize leaves.moreover,the pupa weight,length and width of the larvae feeding on maize leaves were significantly higher than those of the larvae feeding on tea leaves.Although the performance of S.frugiperda feeding on tea leaves was significantly lower than that feeding on maize leaves,some weeds species are the host of S.frugiperda and 3^rd instar larvae feeding on tea leaves could pupate successfully.Thus it is reasonable to speculate that if S.frugiperda migrates to the tea plantation or nearby,the larvae may transfer to damage tea plants with some weeds acting as intermediate.